String XOR Ruby Extension

fast_xor is a simple extension which provides fast in-place String XOR functions (suitable for cryptography).

How do you use it?

  require 'xor'

  # two-argument version
  a, b = 'a string', 'another string'
  a.xor!(b)
  a == "\000N\034\000\032\f\034G"

  # three-argument version
  a, b, c = 'a string', 'another string', 'yet another string'
  a.xor!(b, c)
  a == "y+h {bs3"

How fast is "Fast"?

On my computer, about 1,000x faster than pure Ruby (your mileage my vary):

  $ ruby test/benchmark.rb
        user     system      total        real
  Ruby:  2.070000   0.930000   3.000000 (  3.004088)
  C   :  0.010000   0.000000   0.010000 (  0.003045)